Production of polymer fiber for nonwoven production with the addition of inactive mineral fillers is known, in principle, from the prior art.
U.S. Pat. No. 6,797,377 B1 describes a method for production of a cloth from a polymer or polymer mixture with cloth-like structure (“cloth-like properties”), which contains a mineral filler content of up to 10%. To guarantee softness of the fabric with increasing filler content, a filler mixture is used. It was found that the addition of TiO2, in particular, prevents an increased stiffening of the fabric at higher filler contents. According to the teachings of U.S. Pat. No. 6,797,377, a mixture of TiO2 and another mineral filler is therefore exclusively used. A size from 10 to 150 μm is proposed in U.S. Pat. No. 6,797,377 with reference to particle size of the filler.
U.S. Pat. No. 6,797,377 makes no mention of the cloth properties, when the filler content is increased and the addition of TiO2 is simultaneously abandoned. The significance of particle size and particle shape for the properties of the end product at higher filler content is also not disclosed.